Cod sursa(job #1009062)

Utilizator rares96cheseliRares Cheseli rares96cheseli Data 12 octombrie 2013 13:29:10
Problema Dezastru Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.58 kb
#include <fstream>
#include <iomanip>
#include <cmath>
using namespace std;
ifstream f("dezastru.in");
ofstream g("dezastru.out");

int N, K;
double a[26][26], p[26], cmb=1.0;

int main()
{
    f>>N>>K; a[0][0]=1;
    for (int i=1; i<=N; ++i)
        f>>p[i], a[i][0]=1;

    for (int i=1; i<=N; ++i)
        for (int j=1; j<=K; ++j)
            a[i][j]=a[i-1][j]+a[i-1][j-1]*p[i];
    for (int i=2; i<=N; ++i) cmb*=i;
    for (int i=2; i<=K; ++i) cmb/=i;
    for (int i=2; i<=N-K; ++i) cmb/=i;

    g<<fixed<<setprecision(6)<<fabs(a[N][K]/cmb)<<'\n';
    return 0;
}